The Belgian playmaker - who had been granted extra time off after his involvement at Euro 2024 this summer - arrived at City's Etihad Campus sporting a new hairstyle.
City documented De Bruyne's return by posting a video of him walking from the car park to the main building.
In the video, a voice from out of shot is heard shouting 'oooooo top knot' at De Bruyne, who responds by saying: 'I need to cut my hair'.
De Bruyne's new look generated a lot of comments on social media, where fans could not help but notice the similarities with Haaland's famous hairstyle.
One comment on Instagram read: 'Erling Bruyne'. Another fan wrote: 'Haaland effect is really effective'.
A different fan tweeted: 'Handsome version of Halaand'.
This is not the first time that De Bruyne has seemingly copied one of his team-mate's hairstyles.
Midway through the 2023-24 season, the former Chelsea ace was said to be rocking the Jack Grealish look upon his return from an injury absence.
Despite not playing a single minute of City's pre-season, De Bruyne could be in contention to feature against Manchester United in the Community Shield on Saturday.
Last season, De Bruyne was said to have taken stylistic inspiration from Jack Grealish (right)
Saturday's game will be a repeat of last season's FA Cup final, which United won 2-1.
City will then begin the defence of their Premier League title with a trip to Chelsea eight days later.